Straw and grass have been suggested as good feedstock for biofuel plants, but were they really waste?, asked Dr Peter Wylie, a researcher and consultant specialising in environmental issues, in The Courier Mail (1/9/2007, p.58).Grass versus cattle: “Crop stubbles maintain soil carbon levels. Any significant use of crop stubble will not only reduce soil carbon, it will impact in other ways by increasing soil erosion and reducing the water quality of run-off. Growing grass for conversion to biofuel is another idea gaining momentum. Such land use will mostly be in direct competition with beef cattle production. Although the return from biofuel might beat beef economically, if it grows to any extent like the grain ethanol juggernaut in the US, then there will be a lot less beef and much higher prices.

Urban waste the solution: “One of the most likely waste products we have in Australia to convert into biofuel is bagasse – the shredded stems left over from sugar production. The advantage of bagasse is that it is already harvested and transported to a factory. The disadvantage of using it for biofuel is that it is not available for the return of organic matter and nutrients to farm land. The only ‘real’ waste biomass we have is urban waste, which is otherwise dumped in landfill. There is enough waste in each of our major cities for a biodiesel plant. A small power station is being built in Darwin to burn urban waste. But in most of our cities it is cheaper to use natural gas as a fuel. Hefty carbon taxes will be needed to make conversion of waste viable,” Wylie added.